1. Field of the Invention
The present invention relates to a method for preparing nonreactive aminosilicone oils by base-catalyzed equilibration, which are used, in particular, as agents for textile treatment or in polishes.
2. Description of the Background
The preparation of aminosilicone oils has been known for some time. Typically, an aminosilane is equilibrated with a siloxane in the presence of a basic catalyst. In order to obtain nonreactive oils, this equilibration is often preceded by hydrolytic condensation of the aminosilane containing alkoxy groups. The silane in this case should either contain only one Si atom with condensable alkoxy groups, since the presence of more than one such Si atom would otherwise lead to high-viscosity or even gelled products during condensation, or else very mild condensation conditions should be used, which leads to a high Si--OH content in the end product, which in turn has unfavorable effects on storage stability.
EP 0 269 886, for example, describes a method for preparing nonreactive aminosilicone oil starting from aminosilanes that avoids the hydrolytic condensation as a preliminary step. In this case, monomeric silanes that have amino and alkoxy groups and contain only one Si atom with condensable alkoxy groups are equilibrated in a first step with a linear organopolysiloxane that contains monofunctional units (M-units), in the presence of a basic catalyst and in the absence of water, which leads to a reduction of the number of condensable alkoxy groups per molecule by the number of siloxane units incorporated. Water is then added in a second step to the reaction product obtained and the mixture is subjected to a hydrolysis/condensation reaction to remove the reactive alkoxy groups. The end product obtained in this way can then, if needed, be finally subjected again in a third step to base-catalyzed equilibration with organopolysiloxanes, to adjust to the desired viscosity and/or the desired amine content. The amino groups are statistically distributed in the end product.
Unfortunately, the method of EP 0 269 886 has the particular drawback that the first step must be carried out under anhydrous conditions, which can be accomplished industrially only with difficulty.
Thus, a need exists for a method of preparing nonreactive aminosilane oils which overcomes the above disadvantages.